Antidoublets

Antidoublets are a theoretical concept in particle physics, specifically within the realm of grand unified theories (GUTs) and some extensions of the Standard Model. The term refers to hypothetical particles that are the antiparticles of "doublets," which are particles that transform together under certain symmetry groups. For example, in some GUT models, quarks and leptons are unified into larger representations. A doublet might consist of a quark and a lepton. The corresponding antidoublet would then contain the antiparticle of the quark and the antiparticle of the lepton.

The existence of antidoublets is often a consequence of the gauge structure proposed in these theories. If particles are arranged into doublets, then their antiparticles must also form their own distinct representations under the gauge group. The precise nature and properties of antidoublets depend heavily on the specific GUT model being considered. They could be fundamental particles themselves or composite states.

The search for evidence of antidoublets is indirect. Their existence might be inferred from phenomena such as proton decay, which is a predicted but not yet observed process in many GUTs. If proton decay occurs through intermediate particles that are part of these unified representations, then the existence of antidoublets might be implied. However, direct detection of antidoublets is currently beyond the capabilities of experimental particle physics. The theoretical framework in which they are proposed is still under active investigation and development.